PURPOSE: To evaluate the optimum condition of a recording and reproducing operation by an optical disk apparatus itself by a method wherein an optimum reference signal is recorded in an optical disk and the characteristic of the recorded reference signal is separated and measured.

CONSTITUTION: An optical beam is controlled by a reference pattern generator in such a way that at least one out of the power and the phase width of the optical beam is changed according to a predetermined rule. Then, information pits 3 as pit patterns P1, P2,...Pn which are changed by a predetermined rule at interpit distances of d1, d2,...dn are recorded in track guide grooves 1 in a test region on an optical disk, and special marks 2 as synchronizing signals are put. In addition, the mask patterns are reevaluated, and the optimum range of the sensitivity, the optimum recording condition or the like of the optical disk is detected. Consequently, even without using a measuring apparatus for exclusive use, the optimum range of the sensitivity, the optimum recording condition or the like of the optical disk can be evaluated by an optical disk apparatus itself.